Hydrometer Method Improved for Making Particle Size Analyses of Soils1
About: This article is published in Agronomy Journal.The article was published on 1962-09-01. It has received 4268 citations till now. The article focuses on the topics: Hydrometer.
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01 Jan 1986
TL;DR: In this article, the authors describe methods of particle-size analysis for soils, including a variety of classification schemes and standard methods for size distributions using pipet and hydrometer techniques.
Abstract: Book Chapter describing methods of particle-size analysis for soils. Includes a variety of classification schemes. Standard methods for size distributions using pipet and hydrometer techniques are described. New laser-light scattering and related techniques are discussed. Complete with updated references.
8,997 citations
01 Jan 1991
TL;DR: A compilation of methods used for soil and plant analysis at the Analytical Services Laboratory of the Northern Forestry Centre (NoFC) of Forestry Canada's Northwest Region can be found in this paper.
Abstract: This manual is a compilation of methods used for soil and plant analysis at the Analytical Services Laboratory of the Northern Forestry Centre (NoFC) of Forestry Canada's Northwest Region. The intent of this manual is not so much to recom mend certain procedures over others, but to indicate methods used in our labora tory, why these methods are used, their expected precision and accuracy, and their strengths and weaknesses. RESUME Sont reunies dans Ie present guide les methodes utilisees pour l'analyse des plantes et des sols au Laboratoire des services d' analyse du Centre de foresterie du Nord de Forets Canada (region du Nord-Ouest). L' objectif de ce guide n' est pas tant de recommander certaines methodes de preference a d'autres, mais d'indiquer celles qui sont utilisees dans notre laboratorre, la raison de leur utilisation, I' exact itude et la precision que I' on peut attendre de leurs resultats, leurs points forts et leurs points faibles. /nf. Rep. NOR-X-3/9 iii iv In! Rep. NOR-X-319
809 citations
TL;DR: In this article, a series of edaphic climax forests was highly correlated with field measurements of soil N mineralization (26-84 kg ha-- yr-'; r2 = 0.902, P <.001) and with soil silt + clay content.
Abstract: Net aboveground production (4.1-9.5 Mg ha- Iyr-') across a series of edaphic climax forests was highly correlated with field measurements of soil N mineralization (26-84 kg ha-- yr-'; r2 = 0.902, P < .001) and with soil silt + clay content (5-74%; r2 = 0.883, P < .001). Soil N min- eralization was positively correlated with litter production and N and P return in litter. Soil N min- eralization was negatively correlated with litter C:N and C:P ratios and with efficiency of P use in litter production. Efficiency of N use in litter production declined with increasing N mineralization except for inefficient use of N in a hemlock stand at low N mineralization. Changes in litter quality across the mineralization-soil texture gradient were due to species replacement rather than changes in litter quality within each species. Nitrification was not correlated with aboveground production. Both mineralization and nitrification were highly correlated with humus P content. Differences in nitrification among the soils appeared to be related to P04-P supply in the spring and early summer and to NH4-N supply in mid- to late summer.
750 citations
TL;DR: In this paper, the relative contributions of these two groups of organisms to the microbial biomass and activity of soils from five different ecosystems with treatments hypothesized to enhance soil C sequestration were assessed.
Abstract: Fungi and bacteria govern most of the transformations and ensuing long-term storage of organic C in soils. We assessed the relative contributions of these two groups of organisms to the microbial biomass and activity of soils from five different ecosystems with treatments hypothesized to enhance soil C sequestration: (1) desert (an elevation gradient allowed comparison of soil developed in a cooler, moister climate with soil developed in a warmer, drier climate), (2) restored tallgrass prairie (land reverted to native prairie in 1979 and neighboring land farmed to row crops for ∼100 year), (3,4) two forest types (Douglas fir and loblolly pine, unfertilized control and N-fertilized plots), and (5) agricultural land (conventional- and no-till management systems). The selective inhibition technique, using captan (fungicide) and oxytetracycline hydrochloride (bactericide), was used to determine the activities (respiration) of fungi and bacteria in each of these soils and substrate-induced respiration was used to measure total active soil microbial biomass C. Phospholipid fatty acid analysis was used to determine the composition of the soil microbial biomass and determine if the activities and structure of the microbial communities were related. Differences in fungal-to-bacterial (F:B) activities between treatments at a site were greatest at the prairie sites. The restored prairie had the highest F:B (13.5) and high total C (49.9 g C kg −1 soil); neighboring soil farmed to corn had an F:B of 0.85 and total C of 36.0 g C kg −1 soil. Within the pairs of study soils, those that were tilled had lower fungal activities and stored C than those that were managed to native or no-till systems. In all pairs of soils, soils that had higher absolute fungal activities also had more total soil C and when two extreme cases were removed fungal activity was correlated with total soil C ( R 2 =0.85). Thus, in this small set of diverse soils, increased fungal activities, more than F:B ratios, were associated with increased soil C. Practices that involved invasive land management decreased fungal activity and stored soil C compared to similar soils that were less intrusively managed.
538 citations
26 Oct 2015
536 citations